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Orthoceras is a genus of extinct nautiloid cephalopod restricted to Middle Ordovician-aged marine limestones of the Baltic States and Sweden. This genus is sometimes called Orthoceratites. Note it is sometimes misspelled as Orthocera, Orthocerus or Orthoceros.
The Treatise on Invertebrate Paleontology published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and extant invertebrate animals. The prehistoric invertebrates are described as to their taxonomy, morphology, paleoecology, stratigraphic and paleogeographic range. However, taxa with no fossil record whatsoever have just a very brief listing.
The Ascocerida are comparatively small, bizarre Orthoceratoids known only from Ordovician and Silurian sediments in Europe and North America, uniquely characterized by a deciduous conch consisting of a longiconic juvenile portion and an inflated breviconic adult portion that separate sometime in maturity.
Astieridiscus is an extinct lower Cretaceous ammonite. Its shell evolute, covered by dense, simple or branching, slightly flexuous ribs. The sides are slightly flattened, the venter rounded. No umbilical or other tubercles except on innermost whorl. Superficially resembles Olcostephanus.
Barremites is an ammonoid cephalopod belonging to the family Desmoceratidae, that lived during the Hauterivian and Barremian stages of the Early Cretaceous. Its shell is moderately to very involute, with the outer whorl strongly embracing the inner whorls, and variably compressed. Sides are generally smooth and marked with sinuous or falcate collars marking intervals of growth and bearing feeble striae to moderately distinguished ribs.
Paraceltitidae is a family of Middle and Upper Permian cephalopods, that comprise the earliest of the Ceratitida. Paraceltitidids have variably ribbed, discoidally evolute shells with compressed elliptical whorl sections and simple suture lines. Their origin is most likely in the Daraelitidae of the Prolecanitida and they are the apparent source of the Xenodiscidae. All together they lived for some 12 million years, from about 270.6 to about 258 million years ago.
Bisatoceratidae is a family of Late Paleozoic ammonites now included in the Thalassoceratoidea characterized by thick-discoidal to subglobular, involute shells in which lobes are simple. Some forms have spiral ornamentation.
The Tarphycerida were the first of the coiled cephalopods, found in marine sediments from the Lower Ordovician to the Middle Devonian. Some, such as Aphetoceras and Estonioceras, are loosely coiled and gyroconic; others, such as Campbelloceras, Tarphyceras, and Trocholites, are tightly coiled, but evolute with all whorls showing. The body chamber of tarphycerids is typically long and tubular, as much as half the length of the containing whorl in most, greater than in the Silurian Ophidioceratidae. The Tarphycerida evolved from the elongated, compressed, exogastric Bassleroceratidae, probably Bassleroceras, around the end of the Gasconadian through forms like Aphetoceras. Close coiling developed rather quickly, and both gyroconic and evolute forms are found in the early middle Canadian.
Zetoceras is an extinct ammonoid cephalopod genus from the suborder Phylloceratina that lived during the Early and Middle Jurassic in what is now Europe, and is included in the (family) Phylloceratidae.
Bellerophontoidea,, common name "bellerophonts", is a superfamily of extinct planospirally-coiled globose molluscs. This superfamily is generally included within the Gastropoda, but may instead be a group of monoplacophorans. The taxon first appeared late in the Cambrian and continued until late in the Triassic.
Pseudorthocerida is an order of generally straight longiconic Orthoceratoids with a subcentral to marginal cyrtochoanitic siphuncle composed of variably expanded segments which may contain internal deposits that may develop into a continuous parietal lining.. Cameral deposits are common and concentrated ventrally. Apices typically have a slight to moderate exogastric curvature
Orthoceratoidea is a subclass, formerly considered an infraclass or a superorder, that comprises Cephalopoda orders that have orthoconic to slightly cyrtoconic shells and central to subcentral siphuncles in which there may be internal deposits. Currently, Orthoceratoidea comprises the orders Dissidocerida, Ascocerida, Pseudorthocerida, Lituitida and Orthocerida.
Stephanoceratoidea, formerly Stephanocerataceae, is a superfamily of middle- upper Jurassic ammonoid cephalopods within the order Ammonitida containing diverse forms, generally with sharp ribbing and complex suture lines. Aptychi are believed to be mostly granular (Granulaptycus) or concentrially ribbed on the surface (Praestriaptychus)
Anomia is a genus of saltwater clams, marine bivalve mollusks in the family Anomiidae. They are commonly known as jingle shells because when a handful of them are shaken they make a jingling sound, though some are also known as saddle oysters.
Perisphinctoidea, formerly Perisphinctaceae, is a superfamily of Middle Jurassic (Bajocian) to Lower Cretaceous (Barremian) ammonites, commonly with evolute shells with strong ribbing that typically divides about mid flank before crossing the venter.
Hildoceratidae is a family of ammonoid cephalopods from the Lower Jurassic, lower Pliensbachian to lower Bajocian substages, generally with strongly ribbed, involute shells. They are combined with the Hammatoceratidae, Graphoceratidae, and Sonniniidae to make up the Hildoceratoidea.
Perisphinctidae is a family of Middle and Upper Jurassic discoidal ammonites in the order Ammonitida. They have a shell morphology that is mostly evolute, typically with biplicate, simple, or triplicate ribbing. Large forms have simple apertures and smooth body chambers while small forms have lappets and ribbed body chambers.
Neocomitidae is a family of Lower Cretaceous ammonitids comprising genera with strongly ribbed evolute to smooth, fairly involute shells.
Holcodiscidae is an ammonite family placed in the Ammonite superfamily Desmoceratoidea.
Holcodiscus is an ammonite genus placed in the family Holcodiscidae. Species in this genus were fast-moving nektonic carnivores. The type species of the genus is Ammonites caillaudianus.
References
- ↑ Furnish, W.M.; Glenister, B.F. (1964). "Nautiloidea – Ascocerida". In Moore, R.C. (ed.). Treatise on Invertebrate Paleontology, Part K, Mollusca 3 – Mollusca. Treatise on Invertebrate Paleontology. Kansas, MO: Geological Society of America and University of Kansas Press. p. xxviii + 519 p., 361 fig. ISBN 0-8137-3011-2.
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